diff --git a/scripts/install.sh b/scripts/install.sh
index 5e5ee81b47d641d0e3b6fb1f9b4fdb71107e73ec..e130f5d60d706122c63191f50bae13ab33ab884c 100755
--- a/scripts/install.sh
+++ b/scripts/install.sh
@@ -15,7 +15,7 @@ set -ex
 global=false
 static=''
 client=''
-proc=''
+proc='1'
 while getopts gsc:p: OPT; do
   case "$OPT" in
     g)
@@ -37,7 +37,7 @@ while getopts gsc:p: OPT; do
 done
 
 make_install() {
-  if $1; then
+  if [ "$1" = "true" ]; then
     sudo make install
     # Or else the next non-sudo install will fail, because this generates some
     # root owned files like install_manifest.txt under the build directory.
@@ -50,7 +50,7 @@ make_install() {
 TOP="$(pwd)"
 INSTALL="${TOP}/install"
 
-if $global; then
+if [ "${global}" = "true" ]; then
     BUILDDIR="build-global"
 else
     BUILDDIR="build-local"
@@ -71,38 +71,38 @@ if [[ "$OSTYPE" != "darwin"* ]]; then
     sharedLib="--disable-shared"
 fi
 
-if $global; then
+if [ "${global}" = "true" ]; then
   ./configure $sharedLib $CONFIGURE_FLAGS
 else
   ./configure $sharedLib $CONFIGURE_FLAGS --prefix="${INSTALL}/daemon"
 fi
-make -j${proc}
-make_install $global
+make -j"${proc}"
+make_install "${global}"
 
 cd "${TOP}/lrc"
-mkdir -p ${BUILDDIR}
-cd ${BUILDDIR}
-if $global; then
-  cmake .. -DCMAKE_PREFIX_PATH=$CMAKE_PREFIX_PATH -DCMAKE_BUILD_TYPE=Debug $static
+mkdir -p "${BUILDDIR}"
+cd "${BUILDDIR}"
+if [ "${global}" = "true" ]; then
+  cmake .. -DCMAKE_PREFIX_PATH="${CMAKE_PREFIX_PATH}" -DCMAKE_BUILD_TYPE=Debug $static
 else
-  cmake ..  -DCMAKE_PREFIX_PATH=$CMAKE_PREFIX_PATH \
+  cmake ..  -DCMAKE_PREFIX_PATH="${CMAKE_PREFIX_PATH}" \
             -DCMAKE_BUILD_TYPE=Debug \
             -DCMAKE_INSTALL_PREFIX="${INSTALL}/lrc" \
             -DRING_BUILD_DIR="${DAEMON}/src" $static
 fi
-make -j${proc}
-make_install $global
+make -j"${proc}"
+make_install "${global}"
 
 cd "${TOP}/${client}"
-mkdir -p ${BUILDDIR}
-cd ${BUILDDIR}
-if $global; then
-  cmake .. -DCMAKE_PREFIX_PATH=$CMAKE_PREFIX_PATH $static
+mkdir -p "${BUILDDIR}"
+cd "${BUILDDIR}"
+if [ "${global}" = "true" ]; then
+  cmake .. -DCMAKE_PREFIX_PATH="${CMAKE_PREFIX_PATH}" $static
 else
-  cmake ..  -DCMAKE_PREFIX_PATH=$CMAKE_PREFIX_PATH \
+  cmake ..  -DCMAKE_PREFIX_PATH="${CMAKE_PREFIX_PATH}" \
             -DCMAKE_INSTALL_PREFIX="${INSTALL}/${client}" \
             -DRINGTONE_DIR="${INSTALL}/daemon/share/ring/ringtones" \
             -DLibRingClient_DIR="${INSTALL}/lrc/lib/cmake/LibRingClient" $static
 fi
-make -j${proc}
-make_install $global
+make -j"${proc}"
+make_install "${global}"